Engine



July-2o, 1965 R. T. LARSEN 3,195,521

ENGINE Filed Deo. 9, 1963 2 Sheets-Sheet 2 if; f2s/ 56,5, /2 f4 l fzf ifIl [I6/IVE 27/ 242 INVENTOR.

[defer 2PZ/befall `Z47 By Ha, M, M M

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United States Patent O 3,I95,521 ENGINE Robert T. Larsen, Iena-mener:Failsgwis., assigner to @utbcard Marine Corporation, Waukegan, Ill., acorporation of Delaware Fiied Dec. 9, i963, Ser. No. 328,3?13 9 Claims.(CI. 12S-41.47)

The invention relates generally to marine propulsion devices, such asoutboard motors.

The invention provides a sound isolating barrier between the power headand the lower unit or strut. The barrier comprises a pair of mountingplates adapted to be respectively secured to the head and to the lowerunit, and a sheet of resilient material, such as rubber, which is bondedto and between said plates throughout substantially the entire areathereof. Connection of the power head and lower unit to the platestherefore results in a unitary assembly including a layer or barrier ofresilient material which excludes sound and also serves to dampenvibration.

In the preferred construction, the barrier includes means affordingcommunication between an engine exhaust gas discharge port and anexhaust gas passage in the lower unit, together with means affordingcommunication between a water pump in the lower unit and an enginecooling jacket. Preferably, passage of coolant water through the barrieris arranged to effect cooling of the barrier, and particularly, coolingof the resilient material in the area surrounding the iiow of exhaustgas. The barrier also includes an aperture or bore for the passage ofthe engine crankshaft or the lower unit driveshaft to facilitate theirdriving connection.

Other objects and advantages of the invention will become known byreference to the following description and accompanying drawings inwhich FIGURE l is a partially broken away and sectioned view of anoutboard motor embodying various of the features of the invention;

FIGURE 2 is an enlarged view, partially in section, of a portion of theoutboard motor shown in FIGURE l;

FIGURE 3 is a sectional View taken along line 3 3 of FIGURE 2;

FIGURE 4 is an enlarged fragmentary sectional view taken along line 4 4of FIGURE 3;

FIGURE 5 is a View similar to FIGURE 2 showing a modified construction;

FIGURE 6 is a sectional view taken along line d-e of FIGURE 5;

FIGURE 7 is a view similar to FIGURE 5 showing another modiedconstruction;

FIGURE 8 is a fragmentary sectional view taken along line S-8 of FIGURE7;

FIGURE 9 is a fragmentary sectional view taken along line 9-9 of FIGURE7; i

FIGURE l0 is a fragmentary sectional view taken along line IIL-I0 ofFIGURE 7;

FIGURE 11 is a view similar to FIGURES 3 and 5 showing another modifiedconstruction; and

FIGURE l2 is a sectional view taken along line IZ-IZ of FIGURE ll.

Shown in FIGURE l is an outboard motor II of generally conventionalconstruction except that the power head 13 is connected to the lowerunit I5 to form a unitary propulsion unit by a sound isolating barrier17 inrice terposed between the power head and the lower unit. As iscommon practice, the power head I3 includes an internal combustionengine I9 having a crankshaft 21, a coolant jacket 23, and an exhaustgas discharge port 25.

The iower unit I5 is constructed with an exhaust gas discharge passageor conduit 27, and mounts a driveshaft 29 which is drivingly connectedto a propeller 31 and which is also drivingly connected to the enginecrankshaft 2l. In addition, the lower unit 15 supports a water pump 33which is driven by the driveshaft 29 and which communicates with theengine water jacket 23 by means not shown in FIGURES l through 4.

The assemblage of the lower unit I5 and the power head I3 is supportedby vibration and sound damping mountings in a shroud .35 including anengine cover 37, as disclosed in the Watkins Patent No. 3,002,489. Theshroud 35 is pivotally mounted on a swivel bracket 39 which, in turn, issupported by a transom bracket 4I adapted to be mounted on the transom43 of a boat. The power head and lower unit therefore vibrateindependently of and within the shroud 35.

If desired, the motor cover can be directly connected with theassemblage of the power head and lower unit, which assemblage can besupported from a transom bracket by vibration and sound dampingmountings as disclosed in the Irgens Patent No. 2,740,368. However, inorder to take advantage of the present invention, it is desirable toconnect the engine cover to the lower unit independently of any rigidconnection with the power head.

The barrier I7 serves to at least partially exclude the transmission ofsound from the power head 13 to the lower unit I5, to assist in dampingvibrations set up in the power head 13, and to connect the power head 13and the lower unit I5. The barrier I7 comprises a sheet 45 of resilientmaterial which is interposed between and bonded to a pair of mountingplates 47 and 49. The mounting plate t7 is bolted or otherwise securedto the power head 13 while the other mounting plate 49 is bolted orotherwise secured to the lower unit l5. The sheet 45 extends generallycontinuously between the mounting plates 47 and 49 and can be fabricatedof resilient material such as rubber.

The barrier I7 also includes provision for affording communicationbetween the exhaust gas discharge port Z5 of the engine and the exhaustgas passage 27 in the lower unit I5. In the illustrated construction,such means takes the form of an aperture 51 extending through thebarrier, and an exhaust port sleeve 53 which extends from the engine I9through the aperture 5l and to the exhaust gas passage 27 in the lowerunit I5. It is. to be noted that the portion of the aperture 51extending through the lower mounting plate 4:9 is free of direct contactwith the sleeve 53 and with the engine 19 as a whole.

Preferably, the portion of the barrier surrounding the exhaust gasaperture 5I is cooled to prevent deterioration of the resilient materialand to otherwise reduce the temperature in this area. In the embodimentshown in FIGURES 1, 2, and 3, the sheet 45 an-d the adjacent faces ofthe mounting plates 47 and 49 are formed to provide a conduit meansincluding a circular passage 55 generally surrounding the exhaustaperture 5I. At its ends, the passage 55 communicates with respectivebores 57 and 59 extending through the lower mounting plate 49. The

, 3 i bore 57 communicates through rconduit 61 with the discharge portof the water pump 33 while the bore 59 communicates through a conduit 63which empties into the exhaust gas passage 27. Thus, during engineoperation, the portion of the barrier 17 around the exhaust gas aperture51 is continuously cooled.

In addition to the provision for exhaust gas flow, the barrier 17 alsoincludes another aperture 65 for passage of the crankshaft 21 or of thedriveshait 29 to permit their interconnectionin driving engagement. Inthe construction shown in the drawings, the driveshatt 29`extendsthrough the aperture'd without contacting theY barrier 17 and Vissplined tothe crankshaft at a point above the barrier.

When the power head is adapted to be water cooled, provision is alsomade for. the passage of coolant through the barrier. In the embodimentshown in FIGURE 2, separate bores (not shown) are provided for passing'supply and discharge coolant'water through the-barrier. Such coolantflow is preferably employed to cool the portion of the barrier 17Vsurrounding the exhaust gas aperture 51. Thus, in the embodiment shownin FIGURE 5, the vconduit 161 carrying the discharge from the water pump133' communicates with a bore 157 extending through the lower mountingplate 149. In turn, the bore 157 communicates with one end of acircularly extending recessed passage 155 similar to ythe passage 55. Atits other end, the passage 155 is connected with abore 15? which extendsthrough the upper mounting plate 147fand which is in communicationwith'the coolingl jacket 123 of the engine 119. l

Discharge tlow from the engine cooling jacket 123 passies through a bore169 extending through the barrier 117 and communicating with a'conduit163 which, inthe case of a bypass cooling system, discharges into theexhaust gas passage 127 or, inthe case of a recirculating system,discharges into 'a supplyy port in the waterpump 133.' In somerecirculating systems, the .thermostat `controlling'coolantrecirculation'i's located in the power head. Under these circumstances,another borej(not shown)`can beV provided through the barrier; Y j

- In the embodiment shown in FIGURE 7, a pair of circularlyextendingpassages '255e and 2551i, Ylocated respectivelyY inthe mountingplates 247. and 249, are

connected in series to cool the kbarrier'2il7 in thev area of theexhaust gas aperture 251.Y Specically, the conduit 261 extending fromthe water pump discharge communicates with a'bore 257 extending thnoughthe mounting plate 249, which bore is connected to one end of thepassage 255b surrounding the exhaust Agas aperture 251; y

In the embodiment shown inYFIGURE ll, both vthey ycoolant flow to thewater jacket V323 and the discharge flow from the water jacket areemployedto cool the barrier 317 in the area'of the exhaustgas'dischargeKV flow..

Specitically, the conduit slwextending from the water pump dischargecommunicates, through `a bore 357g Vin the mounting plate 345i,k withone end of an Aarcuately shaped passage 355a whichhextendspartiallyrarounid the exhaust gas aperture351. At its other end, thepassage 355a communicates with a bore 357b through the upper 347 andcommunicates with one end of an arcuate passage 355b in the barrier,which passage also extends partially around the exhaust gas aperture.Atv its other end,

' the passage 3551: communicates with a bore 35951 which extends throughthe lower mounting plate 349 Vand which j is in communication with aconduit 363 connected with a discharge outlet or with a supply port onthe water pump, as desired.

As seen in FIGURE 12, the arcuate passages 35551 and 355b substantiallycompletely surround the exhaust gas aperture 351. As in the otherembodiments, an additional 1.' An outboard motor including a power head,a' lower unit, and means lconnecting said power head and said lowerunitincluding a -pair of mounting lplates and a resilient sheet bonded toand between said plates, one

of said plates being connected to said power head and the other of saidplates being connected to said lower unit.

2. An outboard motor including a power head including an internalcombustion'en'g'ine having an exhaust gas discharge port, and acoolantwater jacket, 'a' lower unit including a water pump, and anexhaust gas passage, and barrier means connecting said power head andsaid lower unitand including a pair of mounting plates and a resilientsheet bonded to and between-said plates, one of said plates beingconnected to Vsaid power head and the other Vof said plates beingconnected to vsaid lower'unit, said barrier means also including meansaffording communication through said barrier meansbetween saidV exhaustgas passageand said exhaust gas discharge port, and means Y adordingcommunication through said ybarrier means between said water pump andlsaid Water coolant jacket.

3;"An. outboard motor in accordance-with claim 2 wherein said meansaffording Acommunication between said water pump and said coolant jacketincludes conduit meansk extending through said barrier means in the areaadjacent to saidmeans affording` communication between said exhaustgaspassage and said exhaust gas discharge port. Y

4. An outboard motor' in' accordance with claim3 y wherein'said conduitmeans extendsfsubstantially commounting plate 347.. In turn, the bore357i; communi- Y cates with the engine water jacket 323. .Discharge fromthe engine water jacket. 323 is carried by another bore l359]: whichextends through the upper mounting plate pletely k:around saidmeansaffording communication bel-V tweensaid exhaust gas passage and saidexhaust gas discharge port. Y 5. An outboard motor in accordance withclaim 4 wherein said conduit means includes a passage located Y.at-leastpartially in said resilient/sheet and at least partially encircling saidmeans affording communication Vbetween said exhaust gas passage and.`said exhaust-gas discharge port. f 6. An outboard'motor in `accordancewith claim 4 wherein said conduit means includes passages locatedentirely in saidV mounting platesjand at least partially encircling'saidmeans affording communication between said exhaust gas passage and saidexhaust gas discharge port. '7. An`outboard motorl in accordance withclaim 3 wherein said conduit means Aincludes' a rst passage' at leastpartially encircling said means affording 'communication between saidVexhaust gasV passage and'said exhaust gas discharge porttorsupplyingcoolant Vto said engine jacket, andV arsecond, passage atleastpartially encircling said meansaffording communication between saidexhaust gas passage and said exhaust gas discharge port for dischargingcoolant fromsaidjengine jacket.V

Vsages each `substantially. encircling saidiv means affording 5 6communcaton between said exhaust gas passage and References Cited by theExaminer sald exhaust gas dlscharge port. 1 t UNITED ST AT1-S PATENTS 9.An outboard motor 1n accomance wlth clmm l 2772 6(19 17/5, G nshem 11517 he e* wh n a' 1 *O e @I W 1' 1n sald means after 11g coumuruc nonbetween 8901674 6/59 Rose 115 18 said exhaust gas passage and saidexhaust gas discharge 5 o 1 port comprises an aperture in said barriermeans and said Klehaefer 12?195 X ,L l Mohr s 11S-17 engme mcludes anexhaust gas dlscnarge tube extendmg v through said aperture free ofContact with said other RlCHARD B- WILKNSON, Pllmay Exammeplate. V; KARLJ. ALBRECHT, Examiner.

2. AN OUTBOARD MOTOR INCLUDING A POWER HEAD INCLUDING AN INTERNAL COMBUSTION ENGINE HAVING AN EXHAUST GAS DISCHARGE PORT, AND A COOLANT WATER JACKET, A LOWER UNIT INCLUDING A WATER PUMP, AND AN EXHAUST GAS PASSAGE, AND BARRIER MEANS CONNECTING SAID POWER HEAD AND SAID LOWER UNIT AND INCLUDING A PAIR OF MOUNTING PLATES AND A RESILIENT SHEET BONDED TO AND BETWEEN SAID PLATES, ONE OF SAID PLATES BEING CONNECTED TO SAID POWER HEAD AND THE OTHER OF SAID PLATES BEING CONNECTED TO SAID LOWER UNIT, SAID BARRIER MEANS ALSO INCLUDING MEANS AFFORDING COMMUNICATION THROUGH SAID BARRIER MEANS BETWEEN SAID EXHAUST GAS PASSAGE AND SAID EXHAUST GAS DISCHARGE PORT, AND MEANS AFFORDING COMMUNICATION THROUGH SAID BARRIER MEANS BETWEEN SAID WATER PUMP AND SAID WATER COOLANT JACKET. 